It is really amazing that now we can boot our computer between the existing Windows 7 installation or Windows 8 without sacrifice disk space!

Using a Dynamic Virtual Hard Disk (VHD), you can install Windows 8 to a single file that is stored on your Windows 7 file system, and then boot directly from that Virtual Hard Disk.

We can choose to load either your existing OS or the new Windows 8 at boot time. We are not doing an in-place upgrade nor doing a rebuild but a new install of Windows

It will not work in the following scenarios…

• If you are using BitLocker on your windows 7 Computer
• If you are using Windows XP as your current operating system and can only (officially) use this on an existing Windows 7 or Windows 2008 R2 computer.
• When making the VHD, make sure the “maximum size” that you specify is less than the actual size of your disk.

Let’s download Windows 8 here and browse the BuildWindows.com web site.

Boot from the Windows 8 media to launch the installer. Before clicking “Install Now”, hit Shift+F10 and the command prompt will appear.

Now create the VHD that will be the Windows 8 drive. Run “diskpart” from the CMD window, and then execute the following commands to diskpart:

1. list disk – This shows your currently attached hard disks.
2. select disk 0 – Select the disk where the current Windows 7 is installed.
3. list vol – Show all the volumes that exist on that disk.
4. create vdisk file=”d:\Windows8.vhd” maximum=20000 type=expandable – This creates a Dynamic VHD that can grow to ~20GB in the root of my Windows 7 partition.
5. select vdisk file=”d:\Windows8.vhd” – after selecting this vdisk, the following commands will apply to it
6. attach vdisk – The VHD will be mounted and the disk will be available to the windows installer
7. exit – Exit diskpart

Close the Command Prompt and return to the Install Windows wizard and click Install Now. Now we should see a new Disk 1 listed with Unallocated Space. We’ll get notice “Windows cannot be installed to this disk” but the Next button is enabled. (Windows is great!). Once the installation is complete and gets reboot, we will see a new boot loader that asks you to “Choose an operating system” and we can select either the new install of Windows 8 or (Windows 7) existing OS. Now we can browse around Windows 8 on the Native hardware! Even though it is running from a VHD we can also still access files on your Windows 7 disk.

Can’t figure out how to shut down?

Take the mouse cursor to the bottom left corner of the screen and a small start menu will appear. Click on Settings, then Power and choose Shutdown.